In many areas, check valves are not approved by the building code, even though insurance companies like them.

These are professionals with additional training and a stricter code of ethics.

I would essentially just need to pay the delinquent taxes.They are in a hot zip code area for Pittsburgh, not high home values but good for rentals. $800 or so a month.

In Texas (from what I understand) they only take out the state tax (6%) but you still are responsible for paying the city HOT (if applicable. which in Galveston is 9%)As for property taxes, take a random zip code in Galveston (say 77550), according to the SmartAsset property tax calculator (as well as Zillow) the property tax there is 1.925%.

Code violations?

I don't know what the process would be like to turn an existing structure into a boarding house--but I'd imagine, your larger problem would be with existing zoning, which likely would not permit a boarding/rooming house in a zone where you currently have a single family home.The state maintains information about rooming and boarding houses here: https://www.state.nj.us/dca/divisions/codes/offices/roomingboarding.html but your municipality will have its own zoning laws about what is permissible.

so when a new property comes on the market i can look up the zip and address and know 1) have i ever reviewed this property before and if so what has changed, 2) i have detailed comps for the zip code.  

However, I do feel that as an aspiring real estate investor, it would be remiss of me not to take advantage of the benefits provided by the tax code.

Somewhere between $20/sf and $250/sf, depending on:- Specific scope of work- Type of contractors- Level of finish- Type of house- Time of year- Your negotiating skill- Local codes/requirements- Size of houseIf it's a big house, there's no major mechanical work, you want vinyl flooring and Home Depot level finishes, you're probably in the $20-50/sf range. 

(Raphael had the street numbers and zip code wrong.)